1. Field of the Invention
The present invention is directed generally to a method and apparatus for aligning outer leads of surface-mountable components with solder pads on a printed circuit board during soldering.
2. Description of the Related Art
On surface-mountable components having outer lead spacings of greater than 150 micrometers, it is known to implement outer lead bonding onto mounting locations by two separate systems, first, a component positioning system and, second, a lead soldering system. The positioning system positions the component, or module, in place on a circuit board or other mounting location and, after the module is in place, releases the module system without having fixed the module at the mounting location. The soldering process on the placed module is then begun, which may result in displacement of the module. Displacement results in the outer leads being soldered in incorrect positions, which must thereafter be corrected. The outer leads may even fail to contact the correct solder locations.
Stirrup soldering is generally utilized in mounting surface-mountable components to their mounting locations. It is possible to tack the corner leads in position before undertaking soldering of the rest of the leads using the soldering stirrup. This, however, requires an additional step.
In circuit modules having outer lead spacings of less than 150 micrometers, the stirrup soldering apparatus is usually avoided and single lead soldering is mainly employed, preferable using soldering tips or lasers. However, single lead soldering is extremely time-consuming and extremely difficult to automate. Further, the problem of exactly placing the module in position on the printed circuit board is not overcome by such single lead soldering.